Mac OS 10.13.4, iTunes 12.7.4
Somehow my music library has become screwed up, and almost all of my 28,000-odd tracks aren't where they should be (according to iTunes). I can create a playlist of all the tracks, and I can export that playlist to a text file. But I don't see how to download those tracks to a library.
All of this happened following moving my Film library to an external drive, tho I don't see the connection. My TV Programs appear to be Ok.